1. Field of the Invention
The present invention generally relates to the field of automatic faucets. More particularly, the present invention relates to an automatic faucet that uses both proximity and contact sensors in conjunction with logic that responds to various actions to provide easy and intuitive operation.
2. Description of the Related Art
Automatic faucets have become popular for a variety of reasons. They save water, because water can be run only when needed. For example, with a conventional sink faucet, when a user washes their hands the user tends to turn on the water and let it run continuously, rather than turning the water on to wet their hands, turning it off to lather, then turning it back on to rinse. In public bathrooms the ability to shut off the water when the user has departed can both save water and help prevent vandalism.
One early version of an automatic faucet was simply a spring-controlled faucet, which returned to the “off” position either immediately, or shortly after, the handle was released. The former were unsatisfactory because a user could only wash one hand at a time, while the later proved to be mechanically unreliable.
A better solution was hands-free faucets. These faucets employ a proximity detector and an electric power source to activate water flow, and so can be operated without a handle. In addition to helping to conserve water and prevent vandalism, hands-free faucets also had additional advantages, some of which began to make them popular in homes, as well as public bathrooms. For example, there is no need to touch the faucet to activate it; with a conventional faucet, a user with dirty hands may need to wash the faucet after washing their hands. Non-contact operation is also more sanitary, especially in public facilities. Hands-free faucets also provide superior accessibility for the disabled, or for the elderly, or those who need assisted care.
Typically, these faucets use proximity detectors, such as active infrared (“IR”) detectors in the form of photodiode pairs, to detect the user's hands (or other objects positioned in the sink for washing). Pulses of IR light are emitted by one diode with the other being used to detect reflections of the emitted light off an object in front of the faucet. Different designs use different locations on the spout for the photodiodes, including placing them at the head of the spout, farther down the spout near its base, or even at positions entirely separate from the spout. Likewise, different designs use different physical mechanisms for detecting the proximity of objects, such as ultrasonic signals or changes in the magnetic permeability near the faucet.
Examples of a hands-free faucets are given in U.S. Pat. No. 5,566,702 to Philippe, and U.S. Pat. No. 6,273,394 to Vincent, and U.S. Pat. No. 6,363,549 to Humpert, which are hereby incorporated herein in their entireties.
Although hands-free faucets have many advantages, depending on how they are used, some tasks may best be accomplished with direct control over the starting and stopping of the flow of water. For example, if the user wishes to fill the basin with water to wash something the hands-free faucet could be frustrating, since it would require the user to keep their hand continuously in the detection zone of the sensors. This is especially likely with a kitchen sink faucet, which may be used in many different tasks, such as washing dishes and utensils. Due to its size, the kitchen sink is often the preferred sink for filling buckets, pots, etc. Thus, there is a need for a kitchen faucet that provides water savings, but which does not interfere with other tasks in which a continuous flow is desired.
Each of these control methods has advantages for a particular intended task. Thus, what is needed is a faucet that provides both conventional, touch control, and hands-free operation modes, so that a user can employ the control mode that is best suited to the task at hand. The present invention is directed towards meeting this need, among others.